Communication apparatus and communication method for multi-PRACH transmission

Abstract

The invention provides a communication device and a communication method for multi-PRACH (Physical Random Access Channel) transmission. A communication device includes a communication device including a receiver that receives control information related to a multi-PRACH transmission, and a transmitter that transmits the multi-PRACH transmission based on the control information, the multi-PRACH transmission including a plurality of PRACH transmissions.

Description

Technical Field

[0001] The following disclosure relates to a communication apparatus and a communication method for multiple physical random access channel (multi-PRACH) transmission, and more particularly to a communication apparatus and a communication method for multiple PRACH transmission over multiple RACH opportunities (RO) in new radio (NR). Background Art

[0002] In the current random access channel (RACH) procedure, the user equipment (UE) receives system information block 1 (SIB1) to derive the physical random access channel (PRACH) resources indicating the RACH occasions (RO) in the time and frequency domain resources, and the synchronization signal / PBCH block (SSB) to RO (SSB to RO) mapping, which is the number of SSBs per RO and the number of preambles per SSB per RO R. After that, the UE selects a RO in the initial uplink bandwidth part (UL BWP) to send the PRACH preamble (also known as Msg1 or PRACH transmission), which is called single PRACH transmission. Reference Figure 6 600 , a typical 4-step random access procedure between a UE and a base station or gNodeB (gNB) is shown in FIG. 602 , where a random access preamble (e.g., a PRACH preamble) is sent from the UE to the gNB. At step 604, the UE receives a random access response (RAR) from the gNB. At step 606, a scheduled transmission is sent from the UE to the gNB. At step 608, the UE receives a content resolution for the transmission from the gNB. The UE is not allowed to select another PRACH preamble before the RAR window for the same transmitted PRACH preamble expires.

[0003] If the transmission or reception of the PRACH preamble is unsuccessful, the PRACH preamble may be repeatedly transmitted with a transmit power increasing by a certain configurable offset (i.e., power-ramping) between each transmission until the UE receives Msg2 (e.g., RAR) from the base station or gNB, or until a configurable maximum number of retransmissions has been performed, or until the transmit power on the UE side reaches a configurable maximum power. In the latter two cases, the random access attempt is declared as failed.

[0004] UL channel performance can be challenging in most scenarios in real deployments. There are also emerging vertical use cases that require UL heavy traffic, for example, for video upload or camera monitoring. Studies have identified PRACH as one of the bottleneck channels in terms of coverage performance. However, due to the limited scope of Rel.3. 17 Coverage Enhancement (CovEnh), PRACH coverage has not been enhanced yet. A new work item (WI) for further New Radio (NR) CovEnh has been approved in Rel.3. As Fig.18 As shown, one of the main objectives is to specify the following PRACH coverage enhancement (RAN1, RAN2) [RP-213579]:

[0005] - Implementation of multiple PRACH transmissions with the same beam for a 4-step RACH procedure; and

[0006] - Study and, if justified, specify PRACH transmission with different beams for the 4-step RACH procedure.

[0007] The enhancements for PRACH are targeted to frequency range 2 (FR2) and may also be applied to FR1 when applicable. In addition, the enhancements for PRACH are targeted to the short PRACH format and may also be applied to other formats when applicable.

[0008] However, communication apparatus and methods for multiple PRACH transmission have not been discussed.

[0009] Therefore, a communication device and method are needed to provide a feasible technical solution for multi-PRACH transmission on multiple ROs in NR. In addition, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims in combination with the accompanying drawings and the background technology of the present disclosure. Summary of the invention

[0010] Non-limiting and exemplary embodiments facilitate providing communication apparatus and methods for multiple PRACH transmissions.

[0011] According to a first embodiment of the present disclosure, there is provided a communication apparatus, comprising: a receiver that receives control information related to a multi-PRACH transmission, and a transmitter that transmits the multi-PRACH transmission based on the control information, the multi-PRACH transmission comprising a plurality of PRACH transmissions.

[0012] According to a second embodiment of the present disclosure, there is provided a base station, comprising: a circuit that generates control information related to multiple PRACH transmissions; a transmitter that sends the control information to a communication device; and a receiver that receives the multiple PRACH transmissions from the communication device.

[0013] According to a third embodiment of the present disclosure, there is provided a communication method, including: receiving control information related to multiple PRACH transmissions, and sending multiple PRACH transmissions based on the control information, the multiple PRACH transmissions including multiple PRACH transmissions.

[0014] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof.

[0015] Additional benefits and advantages of the disclosed embodiments will become apparent from the description and drawings. Benefits and / or advantages may be obtained individually from the various embodiments and features of the description and drawings, and these embodiments and features do not need to be provided in full in order to obtain one or more such benefits and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Through the following written description, which is taken as an example only and is combined with the accompanying drawings, a person of ordinary skill in the art will better understand the embodiments of the present disclosure, and the embodiments of the present disclosure will be obvious to a person of ordinary skill in the art, in which:

[0017] Figure 1 An exemplary 3GPP NR-RAN architecture is shown.

[0018] Figure 2 A schematic diagram showing the functional division between NG-RAN and 5GC is depicted.

[0019] Figure 3 A sequence diagram depicting the RRC (Radio Resource Control) connection establishment / reconfiguration procedure.

[0020] Figure 4 Depicted are schematic diagrams illustrating usage scenarios of enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable and low latency communications (URLLC).

[0021] Figure 5 A block diagram illustrating an exemplary 5G system architecture for V2X communications in a non-roaming scenario is shown.

[0022] Figure 6 An example diagram of a 4-step random access procedure is shown.

[0023] Figure 7 An example illustration of PRACH preamble detection from multiple PRACH transmissions in the time domain is shown.

[0024] Fig. 8A and 8B A diagram of multiple PRACH transmissions for different coverage enhancement (CE) levels according to embodiment E1 is shown.

[0025] Fig. 9 A diagram showing multiple PRACH transmissions for different CE levels according to a variation of embodiment E1 is shown.

[0026] Fig.10 A diagram showing multiple PRACH transmissions for different CE levels according to another variation of embodiment E1 is shown.

[0027] Fig.11AAn example diagram of higher layer parameters indicating RO for multiple PRACH transmissions according to embodiment E2 is shown.

[0028] Fig. 11B A diagram of Table 6.3.3.2-3 (Random access configuration for FR1 and unpaired spectrum) of TS 38.211 enhanced to indicate RO for multiple PRACH transmissions according to embodiment E2 is shown.

[0029] Fig.12 A diagram showing how a PRACH preamble may be partitioned according to various embodiments.

[0030] Fig.13 A diagram showing how frequency partitioning may be utilized in accordance with various embodiments.

[0031] Fig.14 A diagram of an initial uplink bandwidth part (ULBWP) for a reduced capability (RedCap) UE and an initial UL BWP for a non-Redcap UE is shown according to an example.

[0032] Fig.15 A diagram of a cross-duplex (XDD) operation according to an example is shown.

[0033] Fig.16 A diagram showing reduced frequency resource allocation per RO for XDD operation according to embodiment E3 is shown.

[0034] Fig.17 A diagram showing reduced frequency resource allocation per RO for RedCap UEs according to embodiment E3 is shown.

[0035] Fig.18 A diagram of SSB to RO mapping for RedCap UE or XDD operation according to a variation of embodiment E3 is shown.

[0036] Fig.19A and 19B A diagram showing increased time domain RO for a RedCap UE according to a variation of embodiment E3 is shown.

[0037] Fig. 20A An example flow chart of the operation of a UE configured with a multi-PRACH transmission mode according to embodiment E1 is shown.

[0038] Fig. 20B A flow chart showing the operation of a UE according to embodiment E2 is shown.

[0039] Fig. 20C A flow chart showing the operation of the RedCap UE according to embodiment E3 is shown.

[0040] Fig.21 A flow chart illustrating a communication method according to various embodiments is shown.

[0041] Fig. 22 Schematic examples of communication devices according to various embodiments are shown.

[0042] Those skilled in the art will appreciate that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the diagrams, block diagrams or flow charts may be exaggerated relative to other elements to help improve understanding of the present embodiment. DETAILED DESCRIPTION

[0043] Some embodiments of the present disclosure will be described by way of example only with reference to the accompanying drawings. Like reference numerals and characters in the drawings represent like elements or equivalents.

[0044] Apart from this, the overall system architecture assumes a NG-RAN (Next Generation Radio Access Network) comprising gNBs, thereby providing NG Radio Access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol terminations to the UE. gNBs are interconnected with each other with the help of Xn interfaces. gNBs are also connected to NGC (Next Generation Core) via Next Generation (NG) interfaces, more specifically to AMF (Access and Mobility Management Function) (e.g., a specific core entity that implements AMF) via NG-C interfaces, and to UPF (User Plane Function) (e.g., a specific core entity that implements UPF) via NG-U interfaces. NG-RAN architecture in Figure 1 (see, for example, 3GPP TS 38.300 v16.3.0, Section 4).

[0045] The user plane protocol stack for NR (see, e.g., 3GPP TS 38.300, Section 4.4.1) includes the PDCP (Packet Data Convergence Protocol, see Section 6.4 of TS 38.300), RLC (Radio Link Control, see Section 6.3 of TS 38.300) and MAC (Medium Access Control, see Section 6.2 of TS 38.300) sublayers, which terminate in the gNB on the network side. In addition, a new access stratum (AS) sublayer (SDAP, Service Data Adaptation Protocol) is introduced on top of PDCP (see, e.g., subclause 6.5 of 3GPP TS 38.300). A control plane protocol stack is also defined for NR (see, e.g., TS 38.300, Section 4.4.2). An overview of the Layer 2 functionality is given in subclause 6 of TS 38.300. The functionality of the PDCP, RLC and MAC sublayers is listed in Sections 6.4, 6.3 and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in subclause 7 of TS 38.300. In addition, sidelink communication was introduced in 3GPP TS 38.300 v16.3.0. The sidelink supports UE-to-UE direct communication using sidelink resource allocation modes, physical layer signals / channels, and physical layer procedures (see, e.g., Section 5.7 of TS 38.300).

[0046] For example, the medium access control layer handles logical channel multiplexing as well as scheduling and scheduling-related functions, including handling different parameter sets.

[0047] The physical layer (PHY) is responsible for, for example, coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping signals to appropriate physical time-frequency resources. It also handles the mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for the transmission of a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels are PRACH, PUSCH, and PUCCH for uplink, and PDSCH (physical downlink shared channel), PDCCH, and PBCH (physical broadcast channel) for downlink. In addition, physical sidelink channels include physical sidelink control channel (PSCCH), physical sidelink shared channel (PSSCH), physical sidelink feedback channel (PSFCH), and physical sidelink broadcast channel (PSBCH).

[0048] NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine type communications (mMTC), which have different requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20Gbps for downlink and 10Gbps for uplink) and user-experienced data rates that are approximately three times higher than those provided by Advanced IMT. On the other hand, in the case of URLLC, there is a strong demand for ultra-low latency (0.5ms for both UL and DL for user plane latency) and high reliability (1-10ms within 1ms). -5 ) puts forward more stringent requirements. Finally, mMTC may preferably require high connection density (1,000,000 devices / km in urban environments) 2 ), large coverage in harsh environments, and extremely long battery life (15 years) for low-cost devices.

[0049] Therefore, an OFDM parameter set (e.g., subcarrier spacing, OFDM symbol duration, cyclic prefix (CP) duration, number of symbols per scheduling interval) that is suitable for one use case may not be well suited for another use case. For example, low-latency services may preferably require shorter symbol durations (and therefore larger subcarrier spacing) and / or fewer symbols per scheduling interval (aka TTI) compared to mMTC services. In addition, deployment scenarios with large channel delay spreads may preferably require longer CP durations than scenarios with short delay spreads. The subcarrier spacing should be optimized accordingly to retain similar CP overhead. NR can support more than one value of subcarrier spacing. Accordingly, subcarrier spacings of 15kHz, 30kHz, 60kHz, ... are currently being considered. The symbol duration Tu and the subcarrier spacing Δf are directly related by the formula Δf=1 / Tu. In a similar manner as in LTE systems, the term "resource element" may be used to represent the smallest resource unit consisting of one subcarrier of the length of one OFDM / SC-FDMA symbol.

[0050] In the new radio system 5G-NR, for each parameter set and carrier, a resource grid of subcarriers and OFDM symbols is defined for uplink and downlink respectively. Each element in the resource grid is called a resource element and is identified based on a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211v16.3.0).

[0051] Figure 2 The functional split between NG-RAN and 5GC is shown. The NG-RAN logical node is gNB or ng-eNB. 5GC has logical nodes AMF, UPF and SMF.

[0052] Specifically, gNB and ng-eNB host the following main functions:

[0053] - Functions for radio resource management, such as radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to UEs in both uplink and downlink (scheduling);

[0054] -IP header compression, data encryption and integrity protection;

[0055] - Selection of the AMF at UE attach when the route to the AMF cannot be determined based on the information provided by the UE;

[0056] - Routing user plane data towards UPF;

[0057] - Routing control plane information towards the AMF;

[0058] -Connection establishment and release;

[0059] - Scheduling and transmission of paging messages;

[0060] - Scheduling and transmission of system broadcast information (originating from AMF or OAM);

[0061] -Mobility and scheduling measurements and measurement reporting configuration;

[0062] -Transport level packet marking in uplink;

[0063] -Session management;

[0064] - Network slicing support;

[0065] -QoS flow management and mapping to data radio bearers;

[0066] -Support UE in RRC_INACTIVE state;

[0067] -NAS message distribution function;

[0068] - Radio access network sharing;

[0069] -Dual connection;

[0070] - Tight interworking between NR and E-UTRA.

[0071] The Access and Mobility Management Function (AMF) hosts the following key functions:

[0072] - Non-Access Stratum (NAS) signalling termination;

[0073] -NAS signaling security;

[0074] - Access layer (AS) security control;

[0075] - Core Network (CN) inter-node signaling for mobility between 3GPP access networks; - Idle mode UE reachability (including control and execution of paging retransmissions);

[0076] -Registration area management;

[0077] -Support for mobility within and between systems;

[0078] -Access authentication;

[0079] -Access authorization, including roaming permission checks;

[0080] - Mobility management control (subscription and policy);

[0081] - Network slicing support;

[0082] -Session Management Function (SMF) selection.

[0083] Additionally, the User Plane Function (UPF) hosts the following key functions:

[0084] - Anchor point for intra-RAT / inter-RAT mobility (when applicable);

[0085] - External PDU session points interconnected to the data network;

[0086] -Packet routing & forwarding;

[0087] -Packet inspection and user plane part of policy rule enforcement;

[0088] -Business volume usage report;

[0089] - Uplink classifier that supports routing of traffic flows to the data network;

[0090] -Support branching points for multi-host PDU sessions;

[0091] - QoS handling in the user plane, such as packet filtering, gating, UL / DL rate enforcement; - Uplink traffic verification (SDF to QoS flow mapping);

[0092] - Downlink packet buffering and downlink data notification triggering.

[0093] Finally, the Session Management Function (SMF) hosts the following key functions:

[0094] -Session management;

[0095] -UE IP address allocation and management;

[0096] -Selection and control of UP function;

[0097] -Configure traffic steering at the User Plane Function (UPF) to route traffic to the correct destination;

[0098] -Control some policy enforcement and QoS;

[0099] - Downlink data notification.

[0100] Figure 3 Some interactions between the UE, gNB and AMF (5GC entity) are shown in the context of the UE transitioning from RRC_IDLE to RRC_CONNECTED for the NAS part (see TS 38.300v16.3.0). The transition steps are as follows:

[0101] 1.UE requests to establish a new connection from RRC_IDLE.

[0102] 2 / 2a.gNB completes the RRC setup process.

[0103] NOTE: The following describes the scenario where the gNB rejects the request.

[0104] 3. The first NAS message piggybacked in RRCSetupComplete from the UE is sent to the AMF.

[0105] 4 / 4a / 5 / 5a. Additional NAS messages may be exchanged between the UE and the AMF, see TS23.502 reference

[22] (3GPP TS23.122: “Non-Access-Stratum (NAS) functions related to Mobile Station inidle mode”).

[0106] 6.AMF prepares UE context data (including PDU session context, security keys, UE radio capabilities and UE security capabilities, etc.) and sends it to the gNB.

[0107] 7 / 7a.gNB activates AS security with UE.

[0108] 8 / 8a.gNB performs reconfiguration to set up SRB2 and DRB.

[0109] 9. The gNB notifies the AMF that the establishment process is completed.

[0110] RRC is a high-level signaling (protocol) used for UE and gNB configuration. Specifically, the transition involves the AMF preparing UE context data (including, for example, PDU session context, security keys, UE radio capabilities and UE security capabilities, etc.) and sending it to the gNB together with the Initial Context Setup Request. The gNB then activates AS security with the UE, which is performed by the gNB sending a SecurityModeCommand message to the UE and by the UE responding to the gNB with a SecurityModeComplete message. Afterwards, the gNB performs reconfiguration to set up signaling radio bearer 2 SRB2 and data radio bearer DRB by sending an RRCReconfiguration message to the UE and receiving RRCReconfigurationComplete from the UE by the gNB in ​​response. For signaling-only connections, the steps related to RRCReconfiguration are skipped because SRB2 and DRB are not set up. Finally, the gNB notifies the AMF that the establishment process is complete with an INITIAL CONTEXT SETUP RESPONSE.

[0111] Figure 4 Some use cases for 5G NR are shown. In the 3rd Generation Partnership Project New Radio (3GPP NR), three use cases that have been envisioned by IMT-2020 to support a wide variety of services and applications are being considered. The specification of Phase 1 for enhanced mobile broadband (eMBB) has been finalized. In addition to further extending eMBB support, current and future work will also involve standardization of ultra-reliable and low-latency communications (URLLC) and massive machine-type communications. Figure 4 Some examples of envisaged usage scenarios for IMT for 2020 and beyond are shown (see for example ITU-R M.2083 Figure 2 ).

[0112] URLLC use cases have stringent requirements on capabilities such as throughput, latency, and availability, and have been envisioned as one of the enablers of future vertical applications such as wireless control of industrial manufacturing or production processes, telemedicine surgery, distribution automation in smart grids, transportation safety, etc. The ultra-reliability of URLLC will be supported by identifying technologies that meet the requirements set by TR 38.913. For NR URLLC in Release 15, the key requirements include a target user plane latency of 0.5ms for UL (uplink) and a target user plane latency of 0.5ms for DL ​​(downlink). The general URLLC requirement for one transmission of a packet is a BLER (block error rate) of 1E-5 for a packet size of 32 bytes, with a user plane latency of 1ms.

[0113] From a physical layer perspective, reliability can be improved in a number of possible ways. The current scope for improving reliability involves defining a separate CQI table for URLLC, more compact DCI formats, repetition of PDCCH, etc. However, as NR becomes more stable and developed (for NR URLLC key requirements), the scope for achieving ultra-reliability may widen. Specific use cases for NR URLLC in Rel.15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0114] In addition, the technical enhancements targeted by NR URLLC are aimed at delay improvement and reliability improvement. Technical enhancements for delay improvement include configurable parameter sets, mini-slot-based scheduling with flexible mapping, authorization-free (configured authorization) uplink, mini-slot-level repetition for data channels, and downlink preemption. Preemption means stopping the transmission for which resources have been allocated, and the allocated resources are used for another transmission that has been requested later, but with lower latency / higher priority requirements. Therefore, the authorized transmission is preempted by the later transmission. Preemption can be applied independently of a specific service type. For example, a transmission for service type A (URLLC) can be used for transmission preemption of service type B (such as eMBB). Technical enhancements for reliability improvement include a dedicated CQI / MCS table for a target BLER of 1E-5.

[0115] The use case of mMTC (Massive Machine Type Communications) is characterized by a very large number of connected devices that typically send relatively small amounts of non-delay sensitive data. The devices are required to be low-cost and have very long battery life. From the NR perspective, utilizing very narrow bandwidth portions is a possible solution to save power from the UE's perspective and achieve long battery life.

[0116] As mentioned above, the range of reliability in NR is expected to widen. A key requirement in all cases (especially required for URLLC and mMTC) is high reliability or ultra-reliability. Several mechanisms can be considered to improve reliability from a radio perspective and a network perspective. In general, there are several key potential areas that can help improve reliability. These areas include compact control channel information, data / control channel repetition, and diversity with respect to frequency, time and / or spatial domains. These areas are generally applicable to reliability, regardless of the specific communication scenario.

[0117] For NR URLLC, further use cases with more stringent requirements have been identified, such as factory automation, transportation industry and power distribution. The more stringent requirements are higher reliability (up to 10 -6level), higher availability, packet sizes up to 256 bytes, time synchronization down to the order of a few μs, where the value can be one or a few μs, depending on the frequency range, and short latency of around 0.5 to 1 ms, in particular a target user plane latency of 0.5 ms, depending on the use case.

[0118] In addition, for NR URLLC, several technical enhancements from a physical layer perspective have been identified. These include PDCCH (Physical Downlink Control Channel) enhancements related to compact DCI, PDCCH repetition, and increased PDCCH monitoring. In addition, UCI (Uplink Control Information) enhancements are related to enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback enhancements. In addition, PUSCH enhancements related to mini-slot level hopping and retransmission / repetition enhancements have been identified. The term "mini-slot" refers to a transmission time interval (TTI) that includes a smaller number of symbols than a slot (a slot including fourteen symbols).

[0119] The 5G QoS (Quality of Service) model is based on QoS flows and supports both QoS flows that require guaranteed flow bit rate (GBR QoS flows) and QoS flows that do not require guaranteed flow bit rate (non-GBR QoS flows). At the NAS level, QoS flows are therefore the finest granularity of QoS differentiation within a PDU session. QoS flows are identified within a PDU session by the QoS Flow ID (QFI) carried in the encapsulation header on the NG-U interface.

[0120] For each UE, the 5GC establishes one or more PDU Sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearer (DRB) together with the PDU Session and may subsequently configure one or more additional DRBs for one or more QoS Flows of that PDU Session (depending on when the NG-RAN does so), e.g. as described above with reference to Figure 3 As shown in Figure 2. NG-RAN maps packets belonging to different PDU sessions to different DRBs. NAS-level packet filters in UE and 5GC associate UL and DL packets with QoS flows, while AS-level mapping rules in UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0121] Figure 5 The 5G NR non-roaming reference architecture is shown (see TS 23.287 v16.4.0, Section 4.2.1.1). Figure 4The application function (AF) exemplarily described in (e.g., an external application server hosting 5G services) interacts with the 3GPP core network to provide services, such as to support the impact of applications on service routing, access network exposure functions (NEF), or interact with the policy framework for policy control (see Policy Control Function, PCF), such as QoS control. Based on operator deployment, application functions that are considered to be trusted by the operator may be allowed to interact directly with related network functions. Application functions that are not allowed by the operator to directly access network functions interact with related network functions using an external exposure framework via NEF.

[0122] Figure 5 Other functional units of the 5G architecture for V2X communication are shown, namely, unified data management (UDM), policy control function (PCF), network exposure function (NEF), application function (AF), unified data repository (UDR), access and mobility management function (AMF), session management function (SMF) and user plane function (UPF) in 5GC, as well as V2X application server (V2AS) and data network (DN), such as operator services, Internet access or third-party services. All or part of the core network functions and application services can be deployed and run on a cloud computing environment.

[0123] The problem to be solved in the present disclosure is that there is no specification on how to perform multiple PRACH transmissions on multiple ROs in NR. If the UE attempts to perform single PRACH transmission within a slot (legacy UE capability) or multiple PRACH transmissions on multiple slots (Release 18 UE capability) by trying multiple ROs based on the same PRACH resource, the gNB is not aware of the multiple PRACH transmissions from the UE, making the PRACH detection performance undesirable.

[0124] exist Figure 7 A prior art solution to this problem based on current PRACH detection for NR as specified in TS 38.141-01 is shown in diagram 700 of . Without knowing the multiple PRACH transmissions, if multiple PRACH transmissions are performed by the UE, the gNB attempts multiple times (e.g., as shown in the first attempt 702, until the m-th attempt 704 of PRACH detection) to detect the PRACH preamble from the multiple PRACH transmissions in the time domain (e.g., to achieve selectivity gain in the time domain). From the gNB's perspective, there is no difference in the PRACH resources for single PRACH transmissions or multiple PRACH transmissions in this solution. Due to the near-far problem, the selectivity gain is reduced compared to the case with dedicated multiple PRACH transmissions. The use of energy accumulation or coherent accumulation is difficult because it is not clear which PRACH resource corresponding to the n-th transmission is used. It should also be noted that coherent accumulation requires high gNB complexity.

[0125] According to the technical solution for solving the above-mentioned problems proposed in the present disclosure, the UE performs multiple PRACH transmissions based on control information related to the multiple PRACH transmission mode (Embodiment E1) or the RACH timing (RO) of multiple PRACH transmissions (Embodiment E2). The multiple PRACH transmission mode or the RO of multiple PRACH transmissions may be different for each CE level. When the RO of multiple PRACH transmissions is related by control information, the multiple PRACH transmissions may be implicitly determined based on the RO. In order to ensure energy accumulation, PRACH detection of the gNB that provides low complexity and reasonable detection gain may be utilized. Coherent accumulation may also be used if the UE transmission is designated as coherent multiple PRACH transmissions. If multiple CE levels are configured, the technical solution may distinguish the noise level according to the required number of PRACH transmissions. Compared with the above-mentioned prior art solutions, the proposed technical solution advantageously achieves better coverage performance gain.

[0126] In embodiment E1, the UE receives a multi-PRACH transmission mode (K ≥ 1 time slots) per CE level to derive a RACH timing (RO) for each PRACH transmission in a plurality of PRACH transmissions (e.g., multiple PRACH transmissions) according to the CE level. The multi-PRACH transmission mode for each CE level may be different from each other. For example, a multi-PRACH transmission mode for a lower CE level (e.g., CE level 1) may include fewer ROs for transmission than a multi-PRACH transmission mode for a higher CE level (e.g., CE level 2). Reference Fig. 8A and Figure 8B 800 and 812, assuming that l0=0 is used (eg, for deriving the starting position l of the RO i Formula l0 in, as further explained in the following paragraphs) and an A3 preamble with a length of 6 symbols, for CE level 1, K=2 time slots (see reference numeral 814), and for CE level 2, K=3 time slots (see reference numeral 816).

[0127] The UE may drop 1 PRACH transmission 802 for CE level 1 and 2 PRACH transmissions 804 and 806 for CE level 2 due to overlap with a slot boundary (e.g., the boundary between two slots as shown in reference numerals 808 and 810). This is useful for purposes of interaction with slot-level frequency hopping (FH); or for cases where the UE may be configured to accommodate power control commands at the beginning of a slot by the gNB; or for flexible cases when the UE is able to monitor and / or receive PDCCH at the start symbol(s) of a slot by the gNB.

[0128] It should be understood that instead of using the term "multiple PRACH transmissions per CE level," there may be multiple PRACH transmissions per number of repetitions of PRACH transmissions, or per one or more reference signal received power (RSRP) thresholds (e.g., as shown in RSRP threshold 1 818 and RSRP threshold 2 820), or per another standard that may be configured by the associated gNB.

[0129] According to a variation of embodiment E1, based on K time slots, the UE may derive a symbol unit The starting position may be based on one of the following alternatives:

[0130] In alternative 1.1, the starting position of the RO for each of the multiple PRACH transmissions is derived by limiting the multiple PRACH transmissions to K time slots, for example, Fig. 8A It can be expressed as in and l0 are specified in TS 38.211. The number of PRACH transmissions per time slot may be the same or different from each other.

[0131] In another alternative 1.2, in the first slot within a slot, the starting positions of the ROs of a subset of multiple PRACH transmissions are derived by restricting them to the first slot. These starting positions of the ROs are repeated in the remaining (K-1) slots, such as Fig. 9 As shown in the diagram 900 of FIG. Assuming l0=0 and an A3 preamble with a length of 6 symbols, K=2 slots for CE level 1 and K=3 slots for CE level 2, in the first slot 902 within the K slots, 2 PRACH transmissions 904 and 906 are defined and are repeated in the subsequent (K-1) slots. In this alternative, it can be expressed as and∑ i l i ≤14,0≤i≤I-1, where and l0 are specified in Technical Specification (TS) 38.211. In addition, the number of PRACH transmissions per time slot is the same.

[0132] In a further variation of embodiment E1, within K time slots, one or more smaller sub-modes may be determined based on one or a combination of the following. First, in alternative 2.1, for conflict handling between derived ROs of one or more PRACH transmissions that overlap with time slot boundaries and / or signals (or channels) with different priorities, the UE may discard only the overlapping one or more PRACH transmissions while keeping the remaining PRACH transmissions being sent. Signals (or channels) with different priorities may refer to downlink receptions or uplink transmissions with higher priority (such as reception of SSBs or reception of PDCCHs for URLLC services). Within a multiple PRACH transmission mode, the number of PRACH transmissions per time slot may be the same or different from each other (for example, using Fig. 8A 800 to handle conflicts at slot boundaries). Advantageously, this is useful for purposes of interacting with slot-level frequency hopping (FH), i.e., a multi-PRACH transmission mode can include multiple FH hops and coherent PRACH detection can be performed per FH hop for frequency selectivity gain.

[0133] In another alternative 2.2, for conflict handling between derived ROs of one or more PRACH transmissions with different priorities of time slot boundaries and / or signals (or channels), the UE may generate a PRACH preamble for each of the one or more PRACH transmissions, and the UE sends all PRACH transmissions in the multiple PRACH transmissions. Fig.10 An example of using both alternatives 1.1 and 2.2 is shown in diagram 1000 of for collision handling with slot boundaries. For example, referring to diagram 1000, assuming l0=0 and using an A3 preamble of length 6 symbols, for CE level 1, K=2 slots, and for CE level 2, K=3 slots. The UE performs 4 PRACH transmissions 1002 and 7 PRACH transmissions 1004 for CE level 1 and CE level 2, respectively. Advantageously, this enables the UE to have more possible PRACH transmission opportunities within K slots to obtain better detection gain. Secondly, the maximum duration of the UE capability is also used to maintain phase continuity and power consistency.

[0134] In embodiment E2, the UE may be configured to receive an indication of a RO indicating multiple PRACH transmissions. Upon receiving the indication, the UE determines multiple ROs for multiple PRACH transmissions based on conventional procedures. In this case, the multiple PRACH transmission mode is implicitly determined from the indicated ROs.

[0135] There may be various ways of signaling for the indication. In option 1, the indication may be through higher layer parameters in a master information block (MIB) and / or a system information block (SIB). Fig.11A An example diagram 1100 of higher layer parameters indicating a RO for multiple PRACH transmissions according to embodiment E2 is shown. This is an example of higher layer parameters indicating a RO for multiple PRACH transmissions (see reference numeral 1102), where the PRACH duration depends on the Preamble_Format (see reference numeral 1104), the starting position of each RO is defined by Start_Position_in_RACH_slot (see reference numeral 1106), and the number of PRACH transmissions is obtained by numberOfPRACH_Repetitions (see reference numeral 1108). In option 2, a table based indication may be used, where the current table for random access configuration is enhanced by adding a new entry to indicate a RO for multiple PRACH transmissions. The enhanced table may be configured or preconfigured, such as Fig. 11B 1110, which is an example of Table 6.3.3.2-3 of TS38.211 (Random access configuration for frequency range 1 (FR1) and unpaired spectrum), which is enhanced to indicate the RO for multiple PRACH transmissions (see table portion 1112). In Table 1110, the current higher layer parameter prach-ConfiguationIndex is reused to indicate the rows of the table. The UE uses the conventional procedure to determine the PRACH duration and the starting position of each of the multiple ROs. It should be understood that options 1 and 2 can also be used together to indicate ROs for multiple PRACH transmissions.

[0136] It is also possible to implement a common variant for embodiments E1 and E2, wherein the dedicated PRACH resources for multiple PRACH transmissions based on CE level configuration include dedicated radio resources and / or PRACH preambles. In the example, Fig.12 1200 shows the preamble partitioning for 2 CE levels. Separate R1 and R2 preambles (reference numerals 1202 and 1204, respectively) for each RO are configured for CE levels 1 and 2, respectively. The UE can use the same frequency resource allocation to send one preamble of the R1 preambles or one preamble of the R2 preambles. In another example, Fig.131300 shows the use of frequency division multiplexing (FDM) partitioning for different CE levels for each RO, where subcarrier offsets are configured for CE levels 1 and 2, respectively. The same set of R preambles of the RO are used for both CE levels, but the UE can select one of the R preambles using different frequency allocations for different CE levels. For example, RO#3 can be configured such that subcarrier offset 1302 will be used for CE level 1, while subcarrier offset 1304 will be used for CE level 2.

[0137] Another problem to be solved in the present disclosure is that it has not been specified how to perform multiple PRACH transmissions with UEs of different BW capabilities. When the BW of the RO used for multiple PRACH transmissions is wider than the BW configured for XDD and the maximum BW of RedCap UEs, respectively, neither embodiments E1 nor E2 are directly applicable to XDD UEs and RedCap UEs.

[0138] Rel-17 NR supports Reduced Capability (RedCap) UEs with reduced maximum BW: 20MHz for FR1 and 100MHz for FR2. If the initial uplink (UL) bandwidth part (BWP) (e.g., for non-RedCap UEs) is wider than the maximum bandwidth (BW) of the RedCap UE, a separate initial UL BWP is always configured for the RedCap UE within its maximum BW during initial access (e.g., during Fig.14 In the diagram 1400, a separate UL BWP 1402 is configured for RedCap UEs, while a separate UL BWP 1404 is configured for non-RedCap UEs). Within a separate initial UL BWP, the RO of the RedCap UE is configured.

[0139] In addition, a new study item on Cross Duplex (XDD) was approved in RAN#94-e [RP-213591] to study sub-band non-overlapping full duplex (SFBD) and potential enhancements to dynamic / flexible time division duplex (TDD). In NR, the slot / frame format includes downlink (DL), uplink (UL) and flexible (F) symbols (or slots), where there are restrictions on DL / UL configurations to avoid UL / DL interference between gNBs and between UEs, and only F symbols (or slots) can be further semi-statically or dynamically configured as DL symbols (or slots) or UL symbols (or slots). For example, refer to Fig.15 In Figure 1500, in Release 15 / 16 / 17, the F symbol (or time slot) is configured as a UL symbol (or time slot) (see reference numeral 1504). In XDD, multiple subbands (BW XDD) can be configured in the F symbol (or time slot) in the time domain, because at the F symbol (or time slot), some UEs can be further configured as DL and other UEs can be further configured as UL. Fig.15 In the diagram 1500, the frequency resource allocation at F symbol (or time slot) is flexibly configured for UE#1 and UE#2 for downlink heavy reception (see reference numeral 1506) of UE#1 and less UL transmission of UE#2; or uplink heavy transmission (see reference numeral 1508) of UE#2 and less DL reception of UE#1, depending on the application. For the gNB side, (quasi) full duplex is required, while for the UE side, half duplex can be used.

[0140] In addition, Rel-17 NR supports Reduced Capability (RedCap) UEs with a reduced maximum BW: 20MHz for FR1 and 100MHz for FR2. If the initial (uplink) UL bandwidth part (BWP) (e.g., for non-RedCap UEs) is wider than the maximum bandwidth (BW) of the RedCap UE, a separate initial UL BWP is always configured for the RedCap UE during initial access (e.g., during Fig.14 In the diagram 1400, a separate UL BWP 1402 is configured for RedCap UEs, while a separate UL BWP 1404 is configured for non-RedCap UEs) within their maximum BW. Within a separate initial UL BWP, the RO of the RedCap UE is configured.

[0141] In addition, a new study item on Cross Duplex (XDD) was approved in RAN#94-e [RP-213591] to study sub-band non-overlapping full duplex (SFBD) and potential enhancements to dynamic / flexible time division duplex (TDD). In NR, the slot / frame format includes downlink (DL), uplink (UL) and flexible (F) symbols (or slots), where there are restrictions on DL / UL configurations to avoid UL / DL interference between gNBs and between UEs, and only F symbols (or slots) can be further semi-statically or dynamically configured as DL symbols (or slots) or UL symbols (or slots). For example, refer to Fig.15 In Figure 1500, in Release 15 / 16 / 17, the F symbol (or time slot) is configured as a UL symbol (or time slot) (see reference numeral 1504). In XDD, multiple subbands (BW XDD ) can be configured in the F symbol (or time slot) in the time domain, because at the F symbol (or time slot), some UEs can be further configured as DL and other UEs can be further configured as UL. Fig.15In the diagram 1500, the frequency resource allocation at F symbol (or time slot) is flexibly configured for UE#1 and UE#2 for downlink heavy reception (see reference numeral 1506) of UE#1 and less UL transmission of UE#2; or uplink heavy transmission (see reference numeral 1508) of UE#2 and less DL reception of UE#1, depending on the application. For the gNB side, (quasi) full duplex is required, while for the UE side, half duplex can be used.

[0142] In embodiment E3, less frequency resource allocation for each RO or less frequency resource allocation for all ROs for multiple PRACH transmission is configured for the UE according to one of the following conditions:

[0143] - The bandwidth of the multiple sub-bands into which the serving cell frequency band is divided (BW XDD ) is narrower than the threshold (e.g., for UEs operating in SBFD / XDD, such as Fig.16 1600).

[0144] - A first UL frequency band of SBFD / XDD, which is narrower than a second UL frequency band of SBFD / XDD.

[0145] - The maximum bandwidth of the UE is narrower than the threshold (e.g., for Fig.17 1700, wherein the RedCap's individual initial UL BWP is configured within the RedCap UE's maximum bandwidth. Within the individual initial UL BWP, the RO of the RedCap UE is determined.

[0146] The threshold value may be the configured initial UL BWP. In addition, the configured initial BWP may be replaced by a set of resource blocks (RBs), a set of sub-bands into which the serving cell frequency band is divided, the entire bandwidth of the RO frequency division multiplexing (FDMed) in one time instance currently configured by the higher layer parameter msg1-FDM, or another value configured by the gNB. Advantageously, the technical solution proposed according to embodiment E3 improves the coverage performance of UEs with different BW capabilities. It should be understood that UL BWP and UL frequency band may be used interchangeably.

[0147] In accordance with Fig.16 In the example of XDD For example, based on BW in the time domain XDD The function determines the allocation of less frequency resources per RO. The function can be expressed as Where FperRO nonXDD is the bandwidth of the RO for non-XDD UEs, and iBWP nonxDDis the configured initial UL BWP for non-XDD UEs. Fig.16 , iBWP nonXDD 1604 will usually be larger than BW XDD 1604 has more BW. This is applicable when the time domain resources include semi-static flexible symbols / time slots. For simplicity, the same value of BW XDD It may also be applied to a set of consecutive flexible and / or uplink time slots.

[0148] Alternatively, if Fig.16 As shown in the right figure of , there are two or more bandwidths of UL bands in XDD. For example, the first UL band with BW_XDD (i.e., at the second time symbol / time slot) is narrower than the second UL band (i.e., at the third time symbol / time slot). In this case, fewer frequency resources of all ROs are allocated for the first UL band (at the second time symbol / time slot), and more frequency resources of all ROs are allocated for the second UL band (at the third time symbol / time slot).

[0149] If the initial UL BWP of a non-RedCap UE is wider than the maximum BW of a RedCap UE, a separate initial UL BWP is configured for the RedCap UE within its maximum BW during initial access. Within the separate initial UL BWP (rather than within the initial UL BWP of the non-RedCap UE), the RO of the RedCap is determined. Fig.17 In the example of , the smaller frequency resource allocations of all ROs are confined within a single initial UL BWP for RedCap UEs. It can be expressed as Where FperRO RedCap and FperRO nonRedCap are the RO bandwidths of RedCap UE and non-RedCap UE in a time instance, siBWP RedCap Is the separate initial UL BWP, iBWP of RedCap UE RedCap is the initial UL BWP for non-RedCap UEs. SubcarrierOffset_CE(i,j) for RedCap UEs RedCap Can be configured individually or from non-RedCap UE's subcarrier offset SubcarrierOffset_CE(i,j) nonRedCap Implicit export. The SSB to RO mapping for RedCap UE is the same as the SSB to RO mapping for non-RedCap UE. For example, refer to Fig.17, although the separate initial UL BWP 1702 for RedCap UEs has less frequency resource allocation than the initial UL BWP 1704 for non-RedCap UEs, both BWPs have the same SSB to RO mapping of 1 / 2.

[0150] Therefore, if the initial UL BWP for non-RedCap UE is not wider than the maximum BW of RedCap UE, embodiment E1 or embodiment E2 may be used to determine that the RO for multiple PRACH transmissions for RedCap UE is the same as the RO for non-RedCap UE. If the initial UL BWP for non-RedCap UE is wider than the maximum BW of RedCap UE, embodiment E3 may be used to determine the RO for multiple PRACH transmissions for RedCap UE in a separate initial UL BWP, but embodiment E1 or embodiment E2 is used to determine the RO for multiple PRACH transmissions for non-RedCap UE in the initial UL BWP.

[0151] In a variation of embodiment E3, a different SSB to RO mapping is proposed to the UE instead. Fig.18 In diagram 1800, for the initial UL BWP 1802 of the RedCap UE or the small uplink band of the XDD UE, the SSB to RO mapping 1806 is 1 (e.g., each SSB is mapped to 1 RO), and for the initial UL BWP 1804 of the non-RedCap UE or the large uplink band of the XDD UE, the SSB to RO mapping 1808 is 1 / 2 (e.g., each SSB is mapped to 2 ROs).

[0152] Alternatively, more time domain RO is proposed to the UE. Fig.19A 1900, a multi-PRACH transmission is done by a RedCap UE at time instance t_0 (see reference numeral 1902) and t_1 (see reference numeral 1904), while it is done by a non-RedCap UE at time instance t_0 (see reference numeral 1906). This advantageously provides more processing time for the RedCap UE transmission compared to the non-RedCap UE since it has limited capabilities. Additionally, it allows the RedCap UE to change directions in a coarse manner in the time domain by using hybrid or analog beamforming so that finer beams can be done within a coarse direction in the frequency domain to send a preamble, for example, a first coarse direction includes SSB#0 and SSB#1 beams at t_0 and a second coarse direction includes SSB#2 and SSB#3 beams at t_1. This may provide better reception for the gNB.

[0153] Furthermore, in another variation of embodiment E3, the number of ROs between each time instance (e.g., symbols / slots at t_0 and t_1 as discussed above, or the second time symbol / slot and the third time symbol / slot as discussed above) can be configured to be different. Fig.19B As shown in diagram 1908, all ROs cannot be restricted to the bandwidth of multiple sub-bands due to the threshold. XDD Or a separate initial UL BWP for RedCap UEs. A subset of ROs (such as RO#0, RO#1, RO#2, RO#3, and RO#4 shown in RO subset 1910) whose bandwidth is limited to the bandwidth of multiple sub-bands BW XDD Or a separate initial UL BWP for RedCap UEs. Meanwhile, the remaining ROs (such as RO#5, RO#6, and RO#7 shown in RO subset 1912) are sent at t_11916.

[0154] Alternatively, the number of ROs in the small UL (sub) band in XDD in the time symbol / time slot may be small, and the number of ROs in the large UL (sub) band in XDD in the time symbol / time slot may be large. As an example, the ROs may be distributed to more time symbols / time slots in the small UL (sub) band in XDD than in the large UL (sub) band in XDD. For example, a subset of ROs whose bandwidth is limited to the small UL (sub) band (such as RO#0, RO#1, RO#2, RO#3, and RO#4 in RO subset 1910) is transmitted at t_0 1914 in the small UL (sub) band in XDD. At the same time, the remaining ROs (such as RO#5, RO#6, and RO#7 in RO subset 1912) are transmitted at t_1 1916 in the small UL (sub) band in XDD.

[0155] In addition, the SSB to RO mapping may be the same or different between the small UL (sub) band and the large UL (sub) band. Alternatively, the SSB to RO mapping of the small UL (sub) band may be the same as the SSB to RO mapping of a portion of the large UL (sub) band. The portion of the large UL band may be the same frequency as the small UL (sub) band. The SSB to RO mapping of another portion of the large UL (sub) band may be discarded or may not be defined in the small UL (sub) band.

[0156] In all embodiments E1 to E3, during the multiple PRACH transmission mode, the UE may be configured to maintain power consistency and phase continuity for coherent PRACH detection. In addition, the UE may be configured to perform multiple PRACH transmissions by using the same beam, referred to as PRACH repetitions. PRACH repetitions may be used together with a power boosting step based on the following alternatives. In the first alternative, PRACH repetitions start only after the UE reaches the maximum transmit power. At the maximum transmit power, the UE increases the number of PRACH transmissions to be sent (which is configurable). If the number of PRACH repetitions reaches the maximum value and there is still no response from the gNB, the process fails. In the second alternative, PRACH repetitions start before the UE reaches the maximum transmit power. For example, at a transmit power of p i If unsuccessful, the UE sends multiple PRACH transmissions with a power increase step of p. i =p i +Δ, where Δ is configurable. If the transmit power reaches the maximum value and there is still no response from the gNB, the procedure fails.

[0157] In all embodiments, during multi-PRACH transmission mode, the UE may be configured to perform multi-PRACH transmissions by using different beams, referred to as “PRACH scanning”. The UE scans the different beams for multiple PRACH transmissions to find the best narrower Tx beam pair prior to any RRC configuration. The UE does not maintain power consistency and phase continuity during multi-PRACH transmission mode. Afterwards, the associated gNB performs power combining only between PRACH transmissions and the gNB indicates the best narrower Tx beam index in Msg2 which will be used by the UE for the following step of the PRACH procedure, i.e., Msg3 transmission.

[0158] In all embodiments, multiple PRACH transmission mode also means multiple PRACH transmission windows / durations / cycles.

[0159] In all embodiments, a combination of preamble formats (eg, formats A and B) may be used within the multiple PRACH transmission mode in order to utilize time domain resources.

[0160] In all embodiments, energy accumulation combining can be used at the gNB. In this case, the UE is then not required to have coherent multiple PRACH transmissions.

[0161] Fig. 20AAn example flow chart of the operation of a UE configured with a multi-PRACH transmission mode according to embodiment E1 is shown. In step 2002, the UE is configured with a multi-PRACH transmission mode per CE level (K≥1 time slot). In step 2004, the UE derives the RACH timing (RO) of the multi-PRACH transmission mode of the CE level based on the RSRP threshold. In step 2006, it is determined whether the RO of one or more PRACH transmissions overlaps with the time slot boundary. If it is determined that this is the case, the process proceeds to step 2008, where the UE only discards one or more PRACH transmissions while maintaining the remaining PRACH transmissions. Otherwise, the process proceeds to step 2010, where the UE maintains all PRACH transmissions. Then, the process proceeds to step 2012, where the UE performs all PRACH transmissions of the remaining PRACH transmissions or multiple PRACH transmissions.

[0162] Fig. 20B A flow chart of UE operation according to embodiment E2 is shown. At step 2016, the UE receives an indication of an RO for each of a plurality of PRACH transmissions (e.g., a multi-PRACH transmission). At step 2018, the UE determines a plurality of ROs for the multi-PRACH transmissions per CE level, wherein each CE level depends on an RSRP threshold based on a conventional procedure. At step 2020, the UE sends a plurality of PRACH transmissions based on the determined plurality of ROs.

[0163] Fig. 20CA flowchart 2022 of RedCap UE operation according to embodiment E3 is shown. This is a general flowchart for allowing RedCap UE to access a serving cell according to the initial UL BWP configured by the gNB for non-RedCap UE. In step 2024, the gNB configures the initial UL BWP, and a separate initial UL BWP for RedCap UE only. In step 2026, it is determined whether the initial UL BWP is wider than the maximum BW of the RedCap UE. If it is determined that this is the case, the process proceeds to step 2030, where a 2-step method is used to determine the RO of multiple PRACH transmissions for the RedCap UE: in step 1, embodiment E1 or embodiment E2 is implemented to formulate the RO of multiple PRACH transmissions for non-RedCap UEs; in step 2, less frequency resource allocation per RO is configured for the RedCap UE in the separate initial UL BWP compared to the frequency resource allocation of the non-RedCap UE. On the other hand, if it is not determined in step 2026 that this is the case, the process proceeds to step 2028, where the RO for multiple PRACH transmissions of RedCap UEs and non-RedCap UEs in the shared initial UL BWP is determined using embodiment E1 or embodiment E2. From step 2028 or step 2030, the process then proceeds to step 2032, where the RedCap UE sends multiple PRACH transmissions in the shared initial UL BWP (from step 2028) or in a separate UL BWP (from step 2030).

[0164] Fig.21 A flow chart 2100 illustrating a communication method according to various embodiments is shown. In step 2102, control information related to a multiple PRACH transmission is received. In step 2104, a multiple PRACH transmission is sent based on the control information, the multiple PRACH transmission comprising a plurality of PRACH transmissions.

[0165] Fig. 22 It is shown that according to Figures 1 to 21 Schematic partial cross-sectional view of a communication device 2200 of various embodiments and example implementations shown. According to various embodiments, the communication device 2200 may be implemented as a UE or a base station.

[0166] The various functions and operations of the communication device 2200 are arranged into layers according to a hierarchical model. In this model, the lower layers report to and receive instructions from the higher layers according to the 3GPP specifications. For simplicity, the details of the hierarchical model are not discussed in this disclosure.

[0167] like Fig. 22As shown, the communication device 2200 may include a circuit 2214, at least one radio transmitter 2202, at least one radio receiver 2204, and at least one antenna 2212 (for simplicity, for the purpose of illustration, in Fig. 22 Only one antenna is depicted in the figure). The circuit 2214 may include at least one controller 2206, which is used to perform the tasks that the at least one controller 2206 is designed to perform with the assistance of software and hardware, including controlling communications with one or more other communication devices in the wireless network. In addition, the circuit 2214 may also include at least one transmission signal generator 2208 and at least one reception signal processor 2210. The at least one controller 2206 may control the at least one transmission signal generator 2208 under the control of the at least one controller 1506 to generate a signal (e.g., a signal indicating a geographic area) to be sent to one or more other communication devices through the at least one radio transmitter 2202, and control the at least one reception signal processor 2210 to process a signal (e.g., a signal indicating a geographic area) received from one or more other communication devices through the at least one radio receiver 2204. The at least one transmission signal generator 2208 and the at least one reception signal processor 2210 may be independent modules of the communication device 2200, which communicate with the at least one controller 2206 to implement the above-mentioned functions, such as Fig. 22 As shown. Alternatively, at least one transmission signal generator 2208 and at least one reception signal processor 2210 may be included in at least one controller 2206. Those skilled in the art will appreciate that the arrangement of these functional modules is flexible and may vary according to actual needs and / or requirements. Data processing, storage and other related control devices may be provided on appropriate circuit boards and / or in chipsets. In various embodiments, at least one radio transmitter 2202, at least one radio receiver 2204 and at least one antenna 2212 may be controlled by at least one controller 1506.

[0168] The communication device 2200 provides the functions required for multiple PRACH transmission. For example, the communication device 2200 may be a UE, and the receiver 2204 may receive control information related to multiple PRACH transmission. The transmitter 2202 may transmit multiple PRACH transmission based on the control information, and the multiple PRACH transmission includes multiple PRACH transmissions.

[0169] The control information may indicate a multiple PRACH transmission mode for one or more transmission slots, and the transmitter 2202 may be further configured to send multiple PRACH transmissions on the one or more transmission slots based on the multiple PRACH transmission mode.

[0170] The control information may also indicate a different multi-PRACH transmission mode for each coverage enhancement (CE) level in one or more CE levels, wherein the circuit 2214 may determine the CE level for the multi-PRACH transmission, and wherein the transmitter 2202 may also send the multi-PRACH transmission based on the multi-PRACH transmission mode corresponding to the determined CE level.

[0171] The control information may also indicate a different number of transmission slots for each of the one or more CE levels, and the transmitter 2202 may be further configured to transmit the multiple PRACH transmissions in the number of transmission slots corresponding to the determined CE level.

[0172] The circuit 2214 may determine a duration and a starting position of each PRACH transmission of the multiple PRACH transmissions within one or more transmission time slots, and the transmitter 2202 may also transmit the multiple PRACH transmissions based on the determined duration and starting position. The circuit 2214 may also be configured to determine one or more smaller sub-modes within the multiple PRACH transmission mode if a condition is met, wherein the condition is to handle a conflict between any PRACH transmission in the multiple PRACH transmissions and a time slot boundary, and / or a conflict between any PRACH transmission in the multiple PRACH transmissions and other uplink transmissions or downlink receptions with a higher priority.

[0173] Circuitry 2214 may identify one or more PRACH transmissions of the multiple PRACH transmissions on one or more slot boundaries of the one or more transmission slots, and transmitter 2202 may also transmit the multiple PRACH transmissions on the one or more transmission slots without transmitting the identified one or more PRACH transmissions.

[0174] Circuit 2214 may identify one or more PRACH transmissions among multiple PRACH transmissions on one or more time slot boundaries of one or more transmission time slots, and generate a PRACH preamble code for each multiple PRACH transmission including the one or more identified PRACH transmissions, and transmitter 2202 may also be configured to send multiple PRACH transmissions, which includes sending the identified one or more PRACH transmissions on one or more time slot boundaries.

[0175] The control information may indicate a plurality of RACH opportunities (ROs) for the multiple PRACH transmissions, and the transmitter 2202 may be further configured to transmit the multiple PRACH transmissions based on the indicated plurality of ROs. The control information may be indicated by one or a combination of downlink control information, table-based information, uplink control information, medium access control control element (MAC CE), or radio resource control (RRC).

[0176] The control information may indicate one or more beams for uplink transmission, and the transmitter 2202 may be further configured to send multiple PRACH transmissions by using only one of the indicated one or more beams. The control information may indicate one or more beams for uplink transmission, and the transmitter 2202 may be further configured to send multiple PRACH transmissions by using a subset of the indicated one or more beams. The transmitter 2202 may also be configured to send multiple PRACH transmissions only after the communication device reaches a maximum transmit power.

[0177] The communication device 2200 may be, for example, a base station, and the circuit may generate control information related to multiple PRACH transmissions. A transmitter 2202 may send the control information to the communication device. A receiver 2204 may receive multiple PRACH transmissions from the communication device.

[0178] (Control signal)

[0179] In the present disclosure, the downlink control signal (information) related to the present disclosure may be a signal (information) transmitted through the PDCCH of the physical layer, or may be a signal (information) transmitted through a higher layer MAC control element (CE) or RRC. The downlink control signal may be a predefined signal (information).

[0180] The uplink control signal (information) related to the present disclosure may be a signal (information) transmitted through the PUCCH of the physical layer, or may be a signal (information) transmitted through the MAC CE or RRC of a higher layer. In addition, the uplink control signal may be a predefined signal (information). The uplink control signal may be replaced by uplink control information (UCI), first-stage sidelink control information (SCI), or second-stage SCI.

[0181] (Base Station)

[0182] In the present disclosure, a base station may be, for example, a transmission reception point (TRP), a cluster head, an access point, a remote radio head (RRH), an eNodeB (eNB), a gNodeB (gNB), a base station (BS), a base transceiver station (BTS), a base station unit, or a gateway. In addition, in side link communication, a terminal may be used instead of a base station. A base station may be a relay device that relays communication between a higher node and a terminal. A base station may also be a roadside unit.

[0183] (Uplink / Downlink / Sidelink)

[0184] The present disclosure may be applied to any one of an uplink, a downlink, and a sidelink.

[0185] The present disclosure can be applied to, for example, uplink channels (such as PUSCH, PUCCH and PRACH), downlink channels (such as PDSCH, PDCCH and PBCH), and sidelink channels (such as physical sidelink shared channel (PSSCH), physical sidelink control channel (PSCCH) and physical sidelink broadcast channel (PSBCH)).

[0186] PDCCH, PDSCH, PUSCH and PUCCH are examples of downlink control channels, downlink data channels, uplink data channels and uplink control channels, respectively. PSCCH and PSSCH are examples of sidelink control channels and sidelink data channels, respectively. PBCH and PSBCH are examples of broadcast channels, respectively, and PRACH is an example of a random access channel.

[0187] (Data Channel / Control Channel)

[0188] The present disclosure may be applied to any one of a data channel and a control channel. The channels in the present disclosure may be replaced with data channels including PDSCH, PUSCH and PSSCH and / or control channels including PDCCH, PUCCH, PBCH, PSCCH and PSBCH.

[0189] (Reference signal)

[0190] In the present disclosure, a reference signal is a signal known to both a base station and a mobile station, and each reference signal may be referred to as a reference signal (RS) or sometimes referred to as a pilot signal. The reference signal may be any one of a DMRS, a channel state information reference signal (CSI-RS), a tracking reference signal (TRS), a phase tracking reference signal (PTRS), a cell-specific reference signal (CRS), and a sounding reference signal (SRS).

[0191] (Time interval)

[0192] In the present disclosure, the time resource unit is not limited to one or a combination of a time slot and a symbol, and may be a time resource unit such as a frame, a superframe, a subframe, a time slot, a time slot subslot, a small time slot, or a time resource unit such as a symbol, an orthogonal frequency division multiplexing (OFDM) symbol, a single carrier-frequency division multiplexing access (SC-FDMA) symbol, or other time resource units. The number of symbols included in a time slot is not limited to any number of symbols exemplified in the above embodiments, and may be other numbers of symbols.

[0193] (frequency band)

[0194] The present disclosure may be applied to any of the licensed frequency band and the unlicensed frequency band.

[0195] (communication)

[0196] The present disclosure can be applied to any one of the communication between a base station and a terminal (Uu-link communication), the communication between a terminal and a terminal (side link communication), and the vehicle-to-everything (V2X) communication. The channels in the present disclosure can be replaced by PSCCH, PSSCH, physical side link feedback channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0197] In addition, the present disclosure can also be applied to any network in a terrestrial network or a network other than a terrestrial network using a satellite or a high altitude pseudo satellite (HAPS) (NTN: non-terrestrial network). In addition, the present disclosure can be applied to a network with a large cell size, and a terrestrial network with a large delay compared to a symbol length or a time slot length, such as an ultra-wideband transmission network.

[0198] (Antenna port)

[0199] An antenna port refers to a logical antenna (antenna group) formed by one or more physical antennas. That is, an antenna port does not necessarily refer to one physical antenna, but sometimes refers to an array antenna formed by multiple antennas, etc. For example, it is not defined how many physical antennas form an antenna port, but the antenna port is defined as the minimum unit through which the terminal is allowed to send a reference signal. The antenna port can also be defined as the minimum unit for multiplication of precoding vector weights.

[0200] As described above, the embodiments of the present disclosure provide an advanced communication system, communication method, and communication device for multiple PRACH transmissions, which advantageously achieve improved performance gain of coverage between multiple PRACH transmissions.

[0201] The present disclosure can be implemented by software, hardware or software in collaboration with hardware. Each functional block used in the description of each of the above embodiments can be implemented in part or in whole by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled in part or in whole by the same LSI or a combination of LSIs. LSI can be formed as a chip alone, or a chip can be formed to include a part or all of the functional blocks. LSI can include data input and output coupled thereto. According to the difference in integration, the LSI here can be referred to as IC, system LSI, super LSI or ultra LSI. However, the technology for implementing integrated circuits is not limited to LSI, and can be implemented by using a dedicated circuit, a general-purpose processor or a dedicated processor. In addition, an FPGA (field programmable gate array) that can be programmed after LSI manufacturing or a reconfigurable processor that can reconfigure the connection and setting of the circuit unit arranged inside the LSI can be used. The present disclosure can be implemented as digital processing or analog processing. If, as a result of the advancement of semiconductor technology or other derivative technologies, future integrated circuit technology replaces LSI, future integrated circuit technology can be used to integrate functional blocks. Biotechnology can also be applied.

[0202] The present disclosure may be implemented by any kind of device, apparatus, or system having a communication function, which is referred to as a communication device.

[0203] Some non-limiting examples of such communication devices include phones (e.g., cellular (cell) phones, smart phones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, digital book readers, telemedicine / telemedicine (remote health and medicine) devices, and vehicles providing communication capabilities (e.g., cars, airplanes, ships), and various combinations thereof.

[0204] Communication devices are not limited to portable or movable, and may also include any kind of device, equipment, or system that is non-portable or fixed, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "things" in the network of the "Internet of Things (IoT)".

[0205] Communications may include exchanging data via, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0206] The communication apparatus may include a device such as a controller or a sensor coupled to a communication device that performs the communication functions described in the present disclosure. For example, the communication apparatus may include a controller or a sensor that generates a control signal or a data signal used by the communication device that performs the communication functions of the communication apparatus.

[0207] The communication devices may also include infrastructure such as base stations, access points, and any other devices, equipment, or systems that communicate with or control devices such as those in the above non-limiting examples.

[0208] It shall be understood that, although some properties of various embodiments have been described with reference to an apparatus, corresponding properties also apply to the method of various embodiments, and vice versa.

[0209] Further described below are statements applicable to various embodiments of the present invention:

[0210] Statement 1. A communications apparatus comprising: a receiver that receives control information related to a multiple PRACH transmission, and a transmitter that transmits the multiple PRACH transmission based on the control information, the multiple PRACH transmission comprising a plurality of PRACH transmissions.

[0211] Statement 2. The communications apparatus of statement 1, wherein the control information indicates a multiple PRACH transmission mode for one or more transmission slots, and wherein the transmitter further transmits the multiple PRACH transmission on the one or more transmission slots based on the multiple PRACH transmission mode.

[0212] Statement 3. The communications apparatus of statement 2, wherein the control information further indicates a different multiple PRACH transmission mode for each of one or more coverage enhancement (CE) levels, wherein the communications apparatus further comprises: circuitry that determines a CE level for the multiple PRACH transmissions, and wherein the transmitter further transmits the multiple PRACH transmissions based on the multiple PRACH transmission mode corresponding to the determined CE level.

[0213] Statement 4. The communications apparatus of Statement 2, wherein the control information further indicates a different number of transmission slots for each of the one or more CE levels, and wherein the transmitter further transmits the multiple PRACH transmissions within the number of transmission slots corresponding to the determined CE level.

[0214] Statement 5. The communication device of Statement 2 further comprising:

[0215] Circuitry is provided to determine a duration and a starting position of each of the multiple PRACH transmissions within the one or more transmission time slots, and wherein the transmitter further transmits the multiple PRACH transmissions based on the determined duration and starting position.

[0216] Statement 6. The communications apparatus of Statement 2, further comprising: circuitry that determines a plurality of RACH occasions (ROs) within a first slot of the one or more transmission slots that include a duration and a starting position of a subset of the multiple PRACH transmissions, and repeats the determined ROs for each remaining slot of the one or more transmission slots; wherein the transmitter further transmits the multiple PRACH transmissions over the one or more transmission slots based on the determined ROs.

[0217] Statement 7. The communications apparatus of Statement 2 further comprising: circuitry that identifies one or more of the multiple PRACH transmissions at one or more slot boundaries of the one or more transmission slots; wherein the transmitter also transmits the multiple PRACH transmissions at the one or more transmission slots without transmitting the identified one or more PRACH transmissions.

[0218] Statement 8. The communications apparatus of Statement 2, further comprising: circuitry that identifies one or more of the multiple PRACH transmissions at one or more slot boundaries of the one or more transmission slots and generates a PRACH preamble for each of the multiple PRACH transmissions including the one or more identified PRACH transmissions; wherein the transmitter also transmits the multiple PRACH transmissions including transmitting the identified one or more PRACH transmissions at the one or more slot boundaries.

[0219] Statement 9. The communications apparatus of Statement 2, further comprising: a circuit that determines a plurality of PRACH resources for the multiple PRACH transmissions based on the multiple PRACH transmission mode, wherein each of the plurality of PRACH resources comprises dedicated radio resources and / or PRACH preambles for different CE levels, and determines a CE level for the multiple PRACH transmissions; wherein the transmitter further transmits the multiple PRACH transmissions based on each of the plurality of PRACH resources corresponding to the determined CE level.

[0220] Statement 10. A communications apparatus as recited in Statement 5, wherein the circuitry determines one or more smaller sub-modes within the multiple PRACH transmission mode if a condition is satisfied, wherein the condition is to handle a conflict between any of the multiple PRACH transmissions and a slot boundary, and / or a conflict between any of the multiple PRACH transmissions and other uplink transmissions or downlink receptions having a higher priority.

[0221] Statement 11. The communications apparatus of Statement 10, wherein the condition is that the multiple PRACH transmission pattern is longer than a maximum duration of the communications apparatus capable of maintaining phase continuity and power consistency.

[0222] Statement 12. The communications apparatus of Statement 1, wherein the control information indicates a plurality of RACH opportunities (ROs) for the multiple PRACH transmissions, and wherein the transmitter further transmits the multiple PRACH transmissions based on the indicated plurality of ROs.

[0223] Statement 13. The communications device of statement 1, wherein the control information is indicated by one or a combination of downlink control information, table based information, uplink control information, a medium access control element (MAC CE), or a radio resource control (RRC).

[0224] Statement 14. The communications apparatus of statement 1, wherein the control information indicates one or more beams to use for uplink transmission, and wherein the transmitter further transmits the multiple PRACH transmission using only one of the indicated one or more beams.

[0225] Statement 15. The communications apparatus of Statement 1, wherein the control information indicates one or more beams to use for uplink transmissions, and wherein the transmitter further transmits the multiple PRACH transmissions using a subset of the indicated one or more beams.

[0226] Statement 16. A communications apparatus as recited in Statement 14 or Statement 15, wherein the transmitter further transmits the multiple PRACH transmission only after the communications apparatus reaches a maximum transmit power.

[0227] Statement 17. A communications apparatus as recited in Statement 14 or Statement 15, wherein the transmitter further transmits the multiple PRACH transmissions before the communications apparatus reaches a maximum transmit power.

[0228] Statement 18. The communications apparatus of Statement 14, wherein the transmitter further transmits a coherent multiple PRACH transmission.

[0229] Statement 19. The communications apparatus of Statement 1 wherein the control information indicates a plurality of preamble formats, and wherein the transmitter further determines a combination of preamble formats from the indicated plurality of preamble formats to transmit the multiple PRACH transmissions.

[0230] Statement 20. A base station comprising: circuitry that generates control information related to multiple PRACH transmissions; a transmitter that transmits the control information to a communication device; and a receiver that receives the multiple PRACH transmissions from the communication device.

[0231] Statement 21. A method of communication, comprising: receiving control information related to a multiple PRACH transmission, and sending the multiple PRACH transmission based on the control information, the multiple PRACH transmission comprising a plurality of PRACH transmissions.

[0232] It will be appreciated by those skilled in the art that many changes and / or modifications may be made to the disclosure shown in the specific embodiments without departing from the spirit or scope of the disclosure as broadly described. Therefore, the present embodiments are to be considered in all aspects as illustrative and not restrictive.

Claims

1. A communication device, comprising: a receiver that receives control information related to multiple PRACH transmissions, and A transmitter transmits a multiple PRACH transmission based on the control information, wherein the multiple PRACH transmission includes a plurality of PRACH transmissions.

2. The communication device according to claim 1, wherein: The control information indicates a multiple PRACH transmission mode for one or more transmission slots, and wherein the transmitter further transmits the multiple PRACH transmission on the one or more transmission slots based on the multiple PRACH transmission mode.

3. The communication device according to claim 2, wherein: The control information further indicates a different multiple PRACH transmission mode for each of one or more coverage enhancement (CE) levels, wherein the communication apparatus further comprises: circuitry that determines a CE level for the multiple PRACH transmissions, and The transmitter further transmits the multiple PRACH transmissions based on a multiple PRACH transmission mode corresponding to the determined CE level.

4. The communication device according to claim 2, wherein: The control information further indicates a different number of transmission slots for each of the one or more CE levels, and wherein the transmitter further transmits the multiple PRACH transmissions within the number of transmission slots corresponding to the determined CE level.

5. The communication device according to claim 2, further comprising: circuitry that determines a duration and a starting position of each of the multiple PRACH transmissions within the one or more transmission time slots; The transmitter further transmits the multiple PRACH transmissions based on the determined duration and starting position.

6. The communication device according to claim 2, further comprising: circuitry that identifies one or more of the multiple PRACH transmissions at one or more slot boundaries of the one or more transmission slots; wherein the transmitter further transmits the multiple PRACH transmissions on the one or more transmission time slots without the identified one or more PRACH transmissions.

7. The communication device according to claim 2, further comprising: circuitry that identifies one or more of the multiple PRACH transmissions at one or more slot boundaries of the one or more transmission slots and generates a PRACH preamble for each of the multiple PRACH transmissions including the one or more identified PRACH transmissions; The transmitter further transmits the multiple PRACH transmissions, including transmitting the identified one or more PRACH transmissions on the one or more time slot boundaries.

8. The communication device according to claim 5, wherein: The circuit further determines one or more smaller sub-modes within the multiple PRACH transmission mode if a condition is met, wherein the condition is to handle a conflict between any PRACH transmission in the multiple PRACH transmissions and a time slot boundary, and / or a conflict between any PRACH transmission in the multiple PRACH transmissions and other uplink transmissions or downlink receptions with higher priority.

9. The communication device according to claim 1, wherein: The control information indicates a plurality of RACH occasions (ROs) for the multiple PRACH transmissions, and wherein the transmitter further transmits the multiple PRACH transmissions based on the indicated plurality of ROs.

10. The communication device according to claim 1, wherein: The control information is indicated by one of downlink control information, table-based information, uplink control information, medium access control element (MAC CE) or radio resource control (RRC), or a combination thereof.

11. The communication device according to claim 1, wherein: The control information indicates one or more beams for uplink transmission, and the transmitter further transmits multiple PRACH transmission by using only one beam of the indicated one or more beams.

12. The communication device according to claim 1, wherein: The control information indicates one or more beams for uplink transmission, and wherein the transmitter further transmits multiple PRACH transmissions by using a subset of the indicated one or more beams.

13. The communication device according to claim 11 or claim 12, wherein: The transmitter also transmits the multiple PRACH transmission only after the communication device reaches a maximum transmit power.

14. A base station, comprising: circuitry that generates control information related to multiple PRACH transmissions; a transmitter, configured to send the control information to a communication device; and A receiver receives the multiple PRACH transmissions from the communications device.

15. A communication method, comprising: receiving control information related to multiple PRACH transmissions, and A multiple PRACH transmission is sent based on the control information, the multiple PRACH transmission comprising a plurality of PRACH transmissions.

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